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µC Implements Pushbutton Light Dimmers: 06/18/98 EDN-Design Ideas / (added
08/05) A project required building a synchronous-demodulator circuit to track a line
drawn on paper. beauty of synchronous-modulator/demodulator approach is
its inherent noise rejection. method rejects nearly all out-of-band noise, wher
from internal drift or external illumination. This rejection is a boon in optical
tracking, where return signal is inevitably buried in 120-Hz ambient light,
amplifier offsets, and temperature drifts. circuit in Figure 1 is inexpensive,
and it operates from 5V dc. circuit scans eight LED/sensor pairs every 22 msec
and stores result in eight sample/hold (S/H) capacitors for interrogation by a
µP-driven ADC. purpose of circuit is to determine which sensor is above
line. |
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0 to 10 Volt Analog Control Protocol: (design circuit added 8/02) |
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1.5 Volt LED Flashers: four circuits with description (added 4/02) |
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10 Channel LED Sequencer: based on4017 (added 4/02) |
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10 Stage Light Sequencer: flashes10 low voltage bulbs, operates at10-25-Volt
voltage, in PDF format, text in Finnish (added 4/02) |
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12 Stage Neon Sequencer (NE 2/NE 51): uses small power 70-Volt neon bulbs
(added 4/02) |
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12 Volt DC Fluorescent Lamp Driver: This fluorescent lamp driver uses a
normal 120 to 6V step-down transformer in reverse to step12V to about350-Volt to drive
a lamp without need to warm filaments. (added 4/02) |
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12 Volt Lamp Dimmer: dimming d1-by controlling duty cycle of a
astable555 Timer oscillator (added 4/02) |
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12 Volt Lamp Fader (Automatic ): (electronic schematic / circuit added
11/05) |
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12 Volt Strobe Circuit: this circuit uses12V DC instead od mains AC. This is
very good idea if you don't want to mess with direct mains voltage connected circuit
or you want to run stroboscope from batteries. (added 4/02) |
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120 VAC Lamp Chaser using Solid State Relays: (electronic circuit added
7/03) |
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120 VAC Lamp Dimmer (Full Wave SCR): (electronic circuit added 10/05)
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120 Volt AC Lamp Chaser using Solid State Relays: This circuit is similar to
LED clock using12 neon indicator lamps instead of LEDs. It operates from2 high
capacity ni-cad cells (2.5 volts) which keep it going for a couple weeks. High voltage
(70 volts) for neon lamps is obtained from a small switching power supply using
a 74HC14 Schmitt trigger Squarewave oscillator, high voltage switching transistor,
and10 mH high Q inductor. Most any small PNP transistors can be used that have a C/E
voltage rating of 80 or more. (added 4/02) |
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120 Volt AC Lamp Dimmer (Full Wave SCR): (circuit added 7/02) |
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120VAC Lamp Chaser using Solid State Relays: (electronic circuit added 4/05) |
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12V DC Fluorescent Lamp Driver: (electronic circuit added 4/05) |
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12V florescent light inverter: (electronic circuit added 2/07) |
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12VDC Fluorescent Lamp Driver: (circuit / schematic design added 11/06) |
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16 Stage Bidirectional LED Sequencer: (circuit added 7/02) |
